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RE: Atwater questions

To: "John F. Kelly Jr." <76067.1750@compuserve.com>,
Subject: RE: Atwater questions
From: "Tibbals, Paul" <PHT1@pge.com>
Date: Thu, 15 May 2003 13:31:08 -0700
John said,

        -----Original Message-----
        From: John F. Kelly Jr. [mailto:76067.1750@compuserve.com]
        -------------------- Begin Original Message --------------------
                Message text written by "Tibbals, Paul"

                " Open diffs take away much of
                        the advantage of powerful cars. "

        -------------------- End Original Message --------------------

        Are you REALLY, REALLY sure about this?
        How do you know this?

        If you were sitting in a room somewhere in middle America writing a 
rule,
        would your statement play heavily on your rule-writing decision?

        Or maybe somebody you greatly respect stated the above. What would 
happen
        if you found out your thoughts were in error?

        --John Kelly

Paul replies:
Just to be clear, that text you quoted was not from me!  It was from Peter, 
replying to me.  

Whether I respect them or not ;) the Board members who wrote the Solo2 rules 
apparently agree with that statement, as one item that seems to be prohibited 
until cars are SUBSTANTIALLY altered (STX, Street Prepared) is a LSD.  

IMO, the open diff definitely limits MY car's performance vs. having an LSD.  I 
feel that in general they are not offered by the manufacturers from more of a 
safety (read: limitation of liability) concern!  Take your average Neanderthal 
untrained driver (non-SCCA member), who has a wallet full enough to drop for a 
pony car with monster V8.  He/she nails the gas in the middle of a corner the 
inside tire spins and the car won't be that upset.  With a limiting/locking 
differential, however, both rear tires lose grip and the car goes off 
bass-ackwards.  Of course it's a cost item as well.  To my great dismay the 
Quaife for my model is a $1300 item  =<8-0  and that's not including 
installation.  If I had sprung for one, then subsequently gotten involved in 
autocross however, I'd be in STX or ESP.  While I do not have personal seat 
time in the same car with an LSD, several people who I know have that exact 
setup with same or much higher power.  These drivers have stated that the 
overall corner performance is improved because they can accelerate earlier and 
harder.  And that the difference is greater in lower gears where wheelspin is 
easier to induce, which is exactly the range that I use during autocross.

So is it your contention that I'm inferring from your tone that an open diff 
slows down a low-powered car as much as a high-powered car?  Or do you think 
that it doesn't slow down a car much?

PaulT

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